On 2006-04-07, Coyoteboy wrote:

Jasen Betts wrote:
possibly... could be neither.

What else could it be?

could be something like this +v
|
|
.--/\/\/\-----|--+--|-----------.
| | | |
| .---------+ `--|---/\/\/\--'
| | | ^
| | . . . .|. . . . |
| | . VCC(8) . |
| | . . |
| `---RES(4) OUT(3)------+----- out
| . 555 .
+-------TH(6) DIS(7)--
| . .
+-------TR(2) CV(5)--
| . .
===== . GND(1) .
| . . . .|. . . .
| |
`-------------+
|
gnd

measure the the input to the tranmitter and get the micro to copy that signal.

Well thats the plan but i was just hoping someone would have already
worked on them and know but theres little evidence on google so I'll
have to crack out the scope.

15 years ago they were using frequency and duty cycle modulation of a the
input signal, this was used to amplitude modulate the carrier

these days AIUI many setups use digital encoding signalling.

Bye.
Jasen